Conventional heat assisted magnetic recording (HAMR) utilizes a laser in a conjunction with magnetic recording technology to write to magnetic media in a disk drive. Light is provided from a laser to a waveguide in a HAMR transducer fabricated on a slider. The light travels through the waveguide toward the ABS and is coupled into a near-field transducer (NFT). The NFT couples light into the media at a spot size smaller than the optical diffraction limit, heating a region of the media. Coils in the transducer energize the main pole to magnetically write to a portion of the media heated by the spot size at a relatively modest field. Thus, data may be written to the media.
In order for HAMR transducers to function as desired, sufficient energy is delivered to heat the media. Various issues may affect the ability of the HAMR transducer to deliver the desired optical power to the NFT and, therefore, to the media. For example, in some cases, misalignments between the laser and the entrance of the waveguide, deformations in the waveguide, nonuniformities in the core material and/or waveguide imperfections may adversely affect the power delivered to the media. Such issues may be exacerbated in the case of a HAMR transducer using an interferometric tapered waveguide (ITWG). An ITWG splits the power provided to the waveguide into multiple arms of the waveguide. Each arm carries a portion of the laser power, or channel. The channels are recombined near the NFT where the arms come together. Changes in the phase and/or power of each channel may adversely affect the manner in which the channels recombine. Power provided to the NFT may be reduced. Accordingly, a mechanism for improving the efficiency of power delivery for a HAMR transducer is desired.